Conventionally, a structure for assembling a control system in which a plurality of constituent elements for vehicle control are hierarchically constructed is known. For example, JP-H5-85228 A discloses the following constitution in six hierarchical levels: the driver's wish is at the hierarchical level having the highest priority; and the hierarchies of the drive train and brake systems are at lower hierarchical levels. According to this prior art, commands flow only from a higher hierarchical level into a lower hierarchical level. In the above-mentioned prior art, a vehicle can be controlled with priority given to the driver's wish related to running stability over wish related to the forward drive of the vehicle. Thus, all the operation elements cannot be operated even at the hierarchical level at which the highest priority is given to the driver's wish. To cope with this problem, JP-H10-250417 A discloses a control method in which only one command transmitting unit is provided at a high hierarchical level, and a coordinating element for devices is disposed at the highest level. That is, a total vehicle coordinator is provided at the first hierarchical level, and a mechanical energy source and a vehicle movement device are provided at the second hierarchical level. Further, hierarchies are formed within the second hierarchical level. For example, within the mechanical energy source, a source coordinator is provided at the first hierarchical level, and individual elements, such as engine, clutch, and transmission, related to mechanical energy are disposed at the second hierarchical level. Within the vehicle movement device, a vehicle movement coordinator is disposed at the first hierarchical level, and individual elements, such as steering, drive train, brake, and chassis, related to vehicle movement are disposed at the second hierarchical level.
According to JP-H5-85228 A, for example, individual control devices for individual elements, such as steering, wheel drive, power train, brake, and engine, are distributed among hierarchies. Instructions are given only in the direction from a higher hierarchical level into a lower hierarchical level with a physical quantity which determines the interface between individual hierarchical levels. As mentioned above, in the hierarchical structure in the prior art, commands are transmitted only from a higher hierarchy into a lower hierarchy.
A control system having the chain of command/instruction only in the direction from higher level to lower level poses a problem. As an example, the following assumption will be made: a constituent element at a lower hierarchical level or a sensor whose signals are processed at the lower hierarchical level fails. Thus, the constituent elements at a higher hierarchical level than that of the failed constituent element recognize that a failed constituent element exists at the lower hierarchical level. At the same time, they must perform the operation of computing and excluding the functions and performance or influences of the constituent element which failed at the lower hierarchical level.
Control systems for vehicles are rich in product variety with respect to each car model or vehicle grade, and high-value added vehicles are large in number of sensors and economy cars are small in number of sensors. In this case, the constituent elements themselves at the higher hierarchical level or control at the higher hierarchical level must be modified depending on whether a sensor provided in the constituent element or the constituent element itself exists at the lower hierarchical level or not.
The prior art is considered only from the viewpoint of how individual control devices for individual elements, such as steering, power train, and engine, should be hierarchically structured. For example, suggestions as to how the idea (control structure) which is based on when a common control system is constructed in individual hierarchies should be developed are not present in the prior art. Or, suggestions as to how the idea (control structure) on which a control system for managing individual elements in a lump at a higher level is based should be developed are not present in the prior art.
JP-H10-250417 A includes a description that status information and conflict information are fed back and communicated between devices A and B. However, JP-H10-250417 A shows only such a constitution that requests from devices at the second hierarchical level are coordinated at the first hierarchical level as seen from the general viewpoint; and commands are issued to the second hierarchical level. In other words, with respect to hierarchical relation, a higher level is taken as a hierarchy for carrying out only coordination, and specific individual elements are provided at lower levels. This also applies to hierarchical structuring within the second hierarchical level, which is lower than the first hierarchical level. An example will be taken. Even the mechanical energy source, which is at the second hierarchical level as seen from the general viewpoint, adopts the following constitution: the mechanical energy source is provided therein with a source coordinator for carrying out only coordination at the higher level and individual elements, such as clutch, at the lower level.
As mentioned above, JP-H10-250417 A contains only the following ideas: the idea of hierarchical structuring based on what functions should be provided at the first hierarchical level and the second hierarchical level and how the control system should be disposed; and the idea of providing a portion for carrying out only coordination at the higher level and individual elements at the lower level in each hierarchy.
According to JP-H10-250417 A, the second hierarchical level as seen from the general viewpoint is divided into a mechanical energy source and a vehicle movement device. The mechanical energy source is provided with individual elements related to mechanical energy, and the vehicle movement device is provided with an individual element group related to vehicle movement. Further, within the vehicle movement device, a drive train and a brake as individual elements related to engine power are taken as one constituent element unit, and the constituent element unit has a torque distributor at a sublevel within the unit. Separately from the constituent elements of drive train and brake, the mechanical energy source is provided therein with an engine coordinator for controlling fuel injection and the like. The above-mentioned patent document includes the following description: operation elements, such as navigation system, are not included in the overall constitution of a vehicle or are positioned at a lower level as much as possible. As mentioned above, in this prior art, the largest framework of individual elements is divided into coordinating portion (first hierarchical level), mechanical portion (second hierarchical level), and movement control portion (second hierarchical level). As a result, control related to the same engine exists as it is divided into that for the mechanical energy source and that for the vehicle movement device at the second hierarchical level. When control for one function exists as it is divided into a plurality of systems, control for one component unit, for example, an engine cannot be completed within one device unit, for example, the vehicle movement device. When a component is changed from car model to car model, therefore, the restructuring of control, programming, and adaptation must be carried out with other devices also included. In case of this prior art, for example, both the vehicle movement device side and the mechanical energy source side must be coordinated when the engine is changed from car model to car model or from grade to grade.
The above-mentioned patent document considers the navigation system just as an operation element operated by an occupant. In the patent document, the following technical philosophy does not exist: map information, a global positioning system (GPS), and the like exist in the navigation system, and the navigation system can be aggressively utilized for vehicle control.
Consequently, the present invention is intended to provide a vehicle control information conveyance structure as a control platform in vehicles for solving any, any combination, or all of the above-mentioned problems, a vehicle control device using this conveyance structure, and a vehicle control simulator using this conveyance structure.